Molecular-dynamics simulation for liquid chromatographic interactions: effect of mobile phase composition

Area of Science:

• Analytical Chemistry
• Computational Chemistry
• Physical Chemistry

Background:

• High-Performance Liquid Chromatography (HPLC) is a crucial separation technique.
• Understanding solute retention mechanisms is vital for method development.
• Mobile-phase composition significantly influences chromatographic separation.

Purpose of the Study:

• To investigate the impact of mobile-phase composition on solute retention in HPLC using molecular dynamics simulations.
• To characterize the conformational changes of octadecylsilane (ODS) ligands in response to solvent variations.
• To elucidate the distribution of solvent and solute molecules within the separation system.

Main Methods:

• Employed molecular-dynamics simulations to model the HPLC system.
• Constructed distribution profiles of interatomic distances to analyze ODS ligand conformation.
• Analyzed distribution profiles between solvent and ODS molecules to understand solvent distribution.
• Examined solute distribution profiles (n-propylbenzene) relative to ODS ligand atoms.

Main Results:

• Distinct differences in ODS ligand conformation were observed with varying solvent compositions.
• Solvent molecule distribution around ODS ligands clearly differed based on mobile-phase composition.
• Calculated solute distribution profiles showed strong consistency with experimental chromatographic retention data.

Conclusions:

• Mobile-phase composition critically influences ODS ligand conformation and solute distribution in HPLC.
• Molecular dynamics simulations provide valuable insights into the molecular mechanisms governing chromatographic retention.
• The simulation results accurately predict and explain observed chromatographic behaviors.